Elliptic chain driving-gear.



nu. 7n2,a4|. 'Patnted 1m 17, |902.

w. r. wlLLvlAMs. f ELLIPTIC CHAIN'DRIVING GEAR.

(Application led June 25, 1901.)

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No. 702,84l. Patented lune I7, |902.-

W. F. WILLIAMS.`

ELLIPTIG CHAIN DRIVING GEAR.I

(Application led June 25, 190'1.)

UNITED STATES PATENT OFFICE.

WILLIAM FREDERICK WILLIAMS, OF LONDON, ENGLAND.

ELLlPTlC CHAIN DRIVING-GEAR.

SPECIFICATION forming part of Letters Patent No. 702,841, dated June 17, 1902. Application filed .Tune 25, 1901. Serial No. 65,926. (Normodel.)

To @ZZ whom t Irl/ty concern:

Be it known that I, WILLIAM FREDERICK WILLIAMS, a resident of 17 and18 Great Pulteney street, Golden Square, London, England, have invented Improvements in Elliptic Chain Driving-Gear, of which the following is a specification.

My invention relates to improvements in elliptic chain driving-gear of bicycles and tricycles of the kind for which previous Letters Patent were granted to me, datedFebruary 24, 1897, No. 126,447, wherein the ratio of the gearing is varied during each stroke of each pedal by the use of an elliptic sprocketwheel for the driving-chain and wherein the sprocket-wheel is shifted in the direction of its own plane by the action of a stationary eccentric, so as to accommodate Aitself to suit the varying length of chain required at different angular positions of the elliptic wheel.

My present improvements have for object to provide for the adjustment of the rectilinear ball-bearings used to diminish the friction between the arms of the elliptic sprocketwheel and the correspondingv arms on the pedal-crank. y Reference is to be had to the accompanying drawings, wherein'- Figure 1 is an outside face view of the elliptic sprocket-wheel. Fig. 2 is a Vsection of the same, taken in the plane of the major axis; and Fig. 3 is an enlarged transverse section through one of the rectilinear ball-bearings of the elliptical sprocket-wheel.

Similar reference numerals denote like parts in all the figures.

1 is the crank-axle.

2 is one of the pedal-cranks.

3 is the elliptic sprocket-wheel, connected with the'crank-axle 1 (so as to turn therewith, but adapted to move in its own plane in the direction of its major axis relatively to the crank-axle) by the sliding engagement of arms 4 4, situated on the major axis, with guide-bearing brackets 5 5, carried by a pair of arms 6 G, fast with the boss 7 of the pedalcrank 2. The arms 4 may be stayed, as at S 8, by transverse arms or curved brackets from the Iim of Jthe wheel, as shown, and the arms 4 terminate at their inner ends in abutment or guide surfaces 9 9, parallel to and equidistant from the minor axis of the wheel,

these surfaces embracing between them the periphery of a stationary eccentric 10, fast with the bracket 1l of the machine-frame, in which the crank-axis has its bearings, as usual. By the revolution of the sprocketwheel about the stationary eccentric the 'sprocket-wheel will be caused to receive a toand-fro traversing motion in its own piane toward and away from the other Wheel to be driven by the chain.

In order to diminish friction between the arms 4 of the elliptical wheel andtheirbearings in the brackets 5, balls 19 are interposed between the relatively moving surfaces of the arm 4 and its bearings, the balls being retained in' V-grooved races 2O 2l, respectively formed in the opposite sides of each arm 4 and in bearing-blocks 23, fitted one at either side of the arm 4 inthe bracket 5, as hereinafter described, there being preferably two or more balls comprised in each set. By means of the ball-bearings thus formed the arms 4 slide without rubbing friction through the brackets 5 5, all relative lateral motion-t'. c., shake or motion perpendicular to the plane of the wheel-being prevented, while the freest possible longitudinal motion of the arms is permitted, at the same time that a secure driving connection is maintained between the crank-axle 1 and the wheel 3. In order to prevent the balls working out, the ends of the grooved races 2O 21, respectively, are closed at the limits of the intended range of motion-in the one case by the grooves 20 being recessed of the required length in the edges of the arm 4 and in the other case by the ends 24 of the brackets 5, (between which ends the blocks 23 are conflned,) forming stops. In order to provide means of adjustment Where by to enable wear of the balls and their races to be taken up, the blocks 23 are fitted to slide within the box-like bracket 5 and between the parallel faces of the end walls 24 thereof, and each block is pressed forward by a screwthreaded sleeve 25, working through a hole tapped in the outer wall of the bracket, the inner end of the sleeve abutting against the back of the block 23 and its outer end being provided with a head or flange 26, notched or otherwise adapted to be turned by a Spanner or other suitable tool. The screw adjustment is locked by means of a locking-nut 27, ap-

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plied to the outer threaded end of a stem 2S, integral with the back of the block 23 and passing axially through the screwed sleeve 25, against the outer end of which the locking-nut bears. The box-like bracket 5 is completed by a cover-plate 29, fixed by screws upon its open side, so as to inclose the working parts and brace together the outerwalls, so as to enable them to resist the driving strain. is an oiliug-slot in the front Wall of the box 5.

I claiml. In rectilinear ball-bearings constituted by a pair of opposed grooves with interposed balls, the combination with a grooved block forming the one ball-race and fitted in a holder so as to be adjustable toward and away from the other ball-race, of a tubular set-screw screwing through the holder and bearing against the back ofthe adjustable block so as to holdvsaid block unyieldingly up to its Work, a screw-threaded stem attached to the block and passing through the tubular set-screw, and a lock-nut screwing on said stem and bearing against the end of the tubular setscrew so as to lock the block in the position to which it has been brought by said set-screw, substantially as'specified.

2L In an elliptical chain driving-gear, the

combination of a pedal-crank, an elliptical sprocket Wheel having diametrical arms, grooves in the opposite sides of the said arms, oppositely-extendingdriving-arms secured to the boss of the pedal-crank and carrying guide-brackets, bearing-blocks fitted one in each bracket at opposite sides of the arms of the sprocket-Wheel so as to be capablegof adj ustment toward and away from the sprocketwheel arms and each provided with a groove of V-section registering with a groove of similar section in the arm, balls in the races formed by said grooves, a tubular set-screw driving-arms to be maintained in all positions Y of adjustment.

WILLIAM FREDERICK WILLIAMS.

'Vitnesses:

W. M. HARRIS, WALTER J. SKERTEN. 

